SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f20bb27520b625d1a05aaf64ce7b007538cdeac8e2feafe61b81f1365f11b14' 
  AND token = 'IfZs3lcDaCs4Eo3VaWgwS/dOhmYUdvr4rcqjVAoJMjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}